1. Field of the Invention
The present invention relates to a cooking appliance containing a substantially flat top plate and at least one cooking heat source.
2. Discussion of the Background
In the field of equipment items intended for home use, evolutions of appliances used in the kitchen have been constant and considerable during recent years, driven by esthetic and/or technical demands.
The design of cooking appliances has undergone numerous modifications. Thus, enameled-sheet stoves using natural-gas or LPG burners as cooking heat sources have been known for many years. The advantages offered by such stoves, related directly to the nature of the aforesaid cooking heat sources, are very familiar: flexibility of use, low thermal inertia, immediate visibility of heating-power adjustments. The drawbacks of these stoves are also well known, such as the presence of a frame-shaped metal grid which must be cleaned frequently.
Moreover, the esthetic appeal of these stoves appears to be increasingly losing favor, even with the recent use of a molded glass plate on which the gas burners are placed.
Cooking tops commonly known as "electric plates" and using electric resistances disposed under circular metal plates as cooking heat sources have also been long known. These cooking tops have the basic advantage of no longer having metal grids, since the cooking utensils are placed directly on the aforesaid heating plates.
Concurrently with the introduction of the integrated kitchen concept, a major change has been made in cooking tops. This change has consisted in using plates of glass-ceramic.
These plates, which are now widely used, enjoy two notable advantages among others, specifically the ease of cleaning (because of the fact that the surface of a glass-ceramic plate is basically flat) and a strikingly novel external appearance, giving them a more modern appeal.
In addition, these cooking plates of glass-ceramic material have been combined with new cooking heat sources such as halogen lamps and induction heat sources.
In parallel with the aforesaid changes made to cooking appliances, the design of cooking utensils has also undergone numerous modifications.
In particular, cooking vessels of the pan or casserole type, although they have retained their primary function of reheating and/or cooking the food contained therein, have undergone considerable evolution in their external appearance and structure.
Some of these modifications have been driven solely by forces of esthetic nature (color, decorative pattern).
Other modifications can be related to the fact that cooking heat sources have also evolved both in their dimensions (dimensions defining the active heating part) and in their nature (halogen-lamp heat sources, induction heat sources).
For example, casserole dishes or pans of ferromagnetic material, which can be adapted to induction heat sources, have been developed.
However, there now exists a need to improve the compatibility between, on the one hand, the parts of cooking appliances other than the cooking heat sources themselves (radiant or halogen-lamp heating element, gas burner, inductor) and, on the other hand, the cooking vessels.
In fact, imperfect compatibility can lead io various drawbacks during use.
In the particular case of cooking tops, the use of specific vessels, for example having large dimensions and/or a particular surface condition, can be difficult on glass-ceramic cooking plates.
For example, it may prove difficult precisely to center the vessels, especially of large dimensions, perpendicular to the cooking heat sources disposed underneath the plate, with the result that their bottom not necessarily being heated homogeneously over their entire surface.
Similarly, from the fact that the vessels are not necessarily limited in their displacement relative to the plate, or in other words they are not confined to a precise zone thereof, they may create surface scratches, which may be harmful to the mechanical resistance of the plate under certain circumstances. From a safety viewpoint, this can sometimes prove dangerous in that unaware persons, for example children, manipulating these same hot vessels may cause them without excessive effort to slide over the plate and finally cause them to fall from the cooking top in question.